Letoff for loom



June 1958 c. P. BERGSTROM 2,837,123

LETOFF FOR LOOM 2 Sheets-Sheet 1 Filed April 21, 1955 INVENTOR CARL. P. BERGSTROM J1me 1958 i c. P. BERGSTROM 2,837,123

LETOFF FOR LOOM 2 Sheets-Sheet 2 Filed April 21, 1955 "l lllllll Hll INVENTOR CARL P. BERGSTROM ATTORNEY LETOFF FOR LOOM Carl Philip Bergstrom, Millbury, Mass, assignor to ,Crompton & Knowles Loom Works, Worcester, Mass.,

a corporation of Massachusetts Application April 21, 1955, Serial No. 502,959 Claims. or. 139- 110 This invention relates to a letolf mechanism for looms and it is the general object of the invention to provide such a mechanism adapted for the weaving of fabrics having a wide range with respect to the number of picks per inch they contain measured along their length.

Under one condition of operation a loom may be called upon to weave a coarse fabric having only a few weft threads per inch while under another condition the loom may be required to weave a much finer fabric having many times more threads to the inch. As heretofore made letoffs which-are well suited for weaving a fabric in one of these ranges may not be well suited for weaving in the other range and it is an important object of the present invention to provide a letoif mechanism including an actuator and gearing intermediate the actuator and the warp beam capable of different settings to enable the letofi to be used over a wide range of fabrics with respect to picks per inch.

It is a further object of the invention to provide a positively driven letoff including a worm wheel and worm therefor driven by a force derived from the aforesaid actuator and transmitted through two gears of unequal sizes, one of the gears rotating with the worm and the other being driven by a clutch unit which is operated by the actuator. For weaving in one range of fabrics the gears will have one setting while for weaving of a different range the gears will be interchanged. Thus, for a coarse fabric the driving gear connected to the clutch unit may be larger than the gear which rotates with the worm, but for a finer fabric the gears will be transposed so that the smaller gear turns with the'clutch unit and the larger gear with the worm.

It is a further object of the invention to interpose between the worm and the gear on its shaft a driving clutch element slidable along the shaft so that the worm canbe disconnected from the aforesaid clutch unit to permit manual reverse turning of the beam. The element may have clutch teeth to mesh with clutch teeth on each of the gears so that whichever gear is on the worm shaft will be able to cooperate with the teeth of the clutch element. 7

It is a still further object of the invention to provide a letoif which will let ofi the proper amount of warp whether the beam be full or nearly empty. This feature of the invention is carried into effect by employing operating means for the previously mentioned clutch unit positioned to utilize varying amounts of working stroke of the actuator. A movable stop is provided for the operating means to determine the amount by which it is to be moved by the actuator and an adjustment is provided between the stop and the whip roll of the loom whereby increasing amounts of the working stroke of the actuator can be utilized to turn the clutch unit as the diameter of the warp on the beam diminishes.

In order that the invention may be clearly understood reference is made to the accompanying drawings which 2,837,123 Patented June 3,1958

"ice

Fig. 1 is a side elevation of a loom having the invention applied thereto, the warp beam being indicated as full and the previously mentioned gearing being set for the weaving of relatively coarse fabrics with only a few picks per inch,

Fig. 2 is an enlarged detail rear elevation of part of the gearing looking in the direction'of arrow 2, Fig. 1,

Fig. 3 is a vertical section on line 3--3, Fig. 2,

Figs. 4, 5 and 6 are detail enlarged vertical sections on lines 44, 55 and 66 respectively, Fig. 3,

Fig. 7 is an enlarged horizontal section on line 7-7, Fig. 3,

Fig. 8 is an enlarged detail section on line 88, Fig. 1, showing the means for adjusting the position of the previously mentioned stop,

Fig. 9 is an enlarged vertical section on line 99, Fig. 1, showing the relationship of the actuator and operating means, I

Fig. 10 is a diagrammatic view similar to Fig. 5 but showing the gears interchanged or transposed with respect to their operating positions,

Fig. 11 is a view similar to Fig. 10 but showing a modified form of the invention in which the gears may be equal,

Figs. 12 and 13 are diagrammatic views showing the mechanism in two different positions, and.

Fig. 14 is a diagrammatic plan view as seen from the rear of the loom and looking in the direction of arrow 14, Fig. 1.

. Referring particularly to Fig. 1, the loom frame 1' supports at its forward lower end a rocker shaft 2 for the lay swords 3. The loom has top and bottom shafts 4 and 5 respectively and the lay beam and reed (not shown) are reciprocated backwardly and forwardly in usual manner from the top shaft 4.

At the rear of the loom there is structure which supports the letotf, this structure including an upright plate 6 having a horizontal arm 7. Bolted to the upright 6 and extending rearwardly therefrom is a support 8 which carries a pivot 9'for an upwardly extending lever 10 on the upper end of which the whip roll 11 is journaled. A warp guide roll 12 is journaled at 13 on supports and the latter is provided with a stop 14 for engagement with a laterally extending lug 15 on the lever 10 to limit rearward movement, that is, movement to the left, of the whip roll. As shown in Fig. 1 the whip roll is in its rearmost position and the warp W extends upwardly from the warp beam B across the guide roll 12 and over the whip roll 11 and the forwardly to the usual harness mechanism designated diagrammatically at 16 and thence to the fell of the cloth 17 to be incorporated into the fabric F. Forward feed of the warp to the right, Fig. 1, is effected by the mechanism to be described but it is to be understood that slight variations in the tension of the warp may exist, an increase in the tension having the effect of moving the whip roll 11 forwardly and normal tension permitting the whip roll to be at or near its rearmost position.

The support 8, see Fig. 14, has pivoted thereon at 21] a lever 21 having a laterally extending arm 22 which bears against the upper arm 23 of a positioning lever 24 pivoted I at 25 to the upright 6. A link 26 is pivoted to and extends illustrate by way of example two embodiments of the invention'and in which:

rearwardly from arm 23 and is pivoted to the lever 10 at 27 by means which permits vertical adjustment between the link and lever 10. A weight lever 30 is pivoted at 31 with respect to the upright 6 and has a laterally extending arm 32 to which is attached an adjustable weight 33. A link 34 connects the weight lever 30 to the lever 21 and transmits the force of the weight 33 through lever 21 to the arms 22 and 23 so that a continuously acting force tends to move the whip'roll rearwardly. A dash pot 35 connected by rod 36 of the lever arm 32 tends to absorb vibration of the weight due to loom operation. As the 3 warp tension increases sufficiently to. move the whip roll to the right, Fig. 1, rod 26 will rock lever 24 and the latter will act through lever 21, link 34 and lever to lift the weight 33.

The support 8 has secured thereto a casting ttl provided with an arcuate slot .41 through which passes a screw 42 which is fastened into a casing 38. The casing houses a worm gear 43 normally rotatable in opposite directions with respect the beam B and a gudgeon 44 of the beam turns in a self-aligning angularly movable bearing 45 supported by the upright 6. Screw 42 is normally tight to hold the casing fixed relatively to the casting but can be loosened to permit the worm gear, the bearing and the casing to pivot in a horizontal plane to facilitate application of a new beam to the loom.

The matter thus far described is of common construction and some of it is duplicated at the opposite end of the loom as suggested by Fig. 14.

An actuator lever is pivoted at 51 with respect to the upright 6 and has an arm 52 thereof connected adjustably as shown in Fig. 1 to a forwardly extending rod 53 pivoted at. 54 to the laysword 3. Lever. .50 has. a rearwardly extending arm 55 formed with a lifter foot 56. extending under the rearwardly extending arm 57 of an operating lever 58, see. Fig. 9. Lever 58. has a forward arm 59 which is connected to a spring 60 anchored with respect to the upright 6 and tending normally to move the operating lever in a counter-clockwise direction as. viewed in Fig. 1.

A stop rod has. a slotted rod head 66: on the forward end thereof, Figs. 1 and 9., and a pin 67 on'arm 59 is movable in slot 64 in the rod head, the pin normally being held by spring 60. against the rod head at the left end of the. slot as viewed in Fig. 1. The left end of rod 65., see Figs. 1 and 8, passes through a block 68. pivoted to the. lower arm 69 of lever 24. Rod 65 also passes through a guide 70 which has front and intermediate arms 71 and 72 respectively on opposite sides. of the. block 68. The guide alsohas a third or rear. arm 73 and a thumb nut 74 between the. arms 72 and. 7.3 has a. screw thread connection with the. screw threaded end 75 of therod 65.. A wing, nut 76- on the. end 75 is provided asa. check means to. hold any position to which the thumb nut. 74 may move therod 65. with respect to the block- 68.,

By means of'the. structure; thus far describedthe position. of the slotted rod head 66 in a backand forth direc; tion canbe adjusted with respect to the. lever 24 and since the latter is; connected to the whip roll. the latter positions the rod head 66' and therefore determines, the position ofthe operating. lever 58.

The casing 38 has, its. lower end 77 shaped. as. shown in Figs. 3. and 7 to receive a worm. 80 which meshes, with the worm wheel 43. The worm is secured to ,a shaftSl which is rotatable, in the. lower end 77 of the casing 38 and extends. to the left, Fig. 3, and has a collar 82 secured thereto. This collar receives the right-hand thrust ofa compression spring 83 the rear endrof which bears against a clutch element 84 the leftendof-which is formed with clutch teeth 85. These teeth mesh with other clutch teeth 86 on a gear 87 which is rotatable freelyon shaft 81. The clutch element84 rotates with shaft 81 by reason of a key 88 and when the parts are in their normal position shown in Fig. 3 rotation of gear 87 in a clockwise direction as viewed in Fig. 2 will cause turning of theworm and the warp beam in a direction to pay off warp.

As shown in Fig. 7 the left end of the lower part 77 of casing 38 has a bearing 90 securedthereto by a screw 91, and a sleeve 92 serving as a bearing for the shaft 81 passes through saidpart 77 and the bearing9 0.- A further purpose of the bearing 90will be describedhereinafter.

A second shaft 95 rotatesin. the bearing90 and also in a bearing 96 secured to the casing 38 at 97. A collar 98 on the left end of shaft 95 and a cotter pin 99' on the right end of the shaft, Fig. 3, position the shaft against 'endwise movement. A second. gear 100.is.ke yed at 101 4 to shaft 95, and mounted on the. latter between the gear and the bearing 90 is a clutch unit C. This unit includes a shell 102 within-which is located a series of clutch members 103 adapted for engagement with a sleeve 104 keyed at 105 to the shaft 95. The shell 102 has a right-hand reduced extension, see Fig. 3, which is keyed at 106 to an arm 107 the right end of which, Fig. 2, is pivoted to an upwardly extending rod 108 having a rod head 109 thereon pivotally connected to the previously describedoperating lever arm 57. The clutch members 103 act to transmit counterclockwise turning of arm 107 to sleeve 104, shaft 95 and the gear keyed to this shaft, but do not transmit clockwise turning of arm 107 to shaft 95.

The clutch element 84 has a circumferential groove 110 to receive a forked arm 111, see Fig. 4, fixed to a slide rod 112 the right end of which as shown in Fig. 7 is slidable in the bearing 90 and the left end .of which slides through the bearing 96 and has a knob 113 secured thereto at its outer end. A lock 115 is pivoted about a stud 117 on bearing 96, see Fig. 7. This lock key is held between collars 118 on the. stud and a shoulder 119 on the stud limits movement of the lock toward the hearing 96.

The knob 113. has a hub 120 formed with a circumferential groove. 121 for the lock. Under ordinary conditions the. lock is out of slot 121 and rests on hub 120, as in Figs. 6 and 7, but when it is desired to disconnect the clutch element 84 from the. gear 87 the knob. 113 will be pressed to the right, Fig. 7, against the action of spring 83 until the lock 115. can fall into the slot 121. Under this lattercondition the clutch teeth 85 of the element 84 will be out of engagement with the clutch teeth 86 of the gear 37 and the shaft 81 can be turned manually independently of the clutch unit C by application ofv a wrench to the squared left end 125 of shaft 81, see Fig. 7.

In the matter thus far described the gear 100 is twice the size of gear 87 and has clutch teeth 126 similar to clutch teeth 86 on smaller gear 67. These teeth 1 26 are not used in the setting of. the invention shown in Figs; 1, 3 and,7, but are-reserved fora reason to be set forth hereinafter.

When theparts are assembled as. already described, and assumingthat the fabric: to be woven. is coarse so that it will, have. comparatively few weft threads per inch of length,.and,assuming furtherthat the beam is full as suggested inE-i'g- 1. thewhip roll will be. in its rearmost position and the; thumb. nut. 74' set so that the pin 67 will engage the rod head 66 at the rear end of.;the slot 64; This will locate. the. operating lever arm 57 about. as shown, in Fig.1 andwhen the actuator lever. 50 rocks clockwise on a working stroke. due. tobackward movem ltof the. lay therewill; be little if any. engagement. of

the; foot 56 with: the leverarm 57. As theloom' operates increasing tensionin the warpxwill move the whip. roll 11 forwardly a slightamount which will, move: the stop rod 65rear1wardly and permit. the spring60 to cause a slight counterclockwise rotation of the operating lever from the dottedline position toithefull line position shown in Fig. 12 so that the operating. lever will .be engaged by the foot 56' near the upper end of the working stroke of the actuator. This will cause a lifting of rod108 which will cause the clutch unit C to turn shaft 95 in a counterclockwise-direction as viewed'in Fig. 4 and the resultant turning of gear 100, in the same direction will cause turning of the gear 87: in a clockwise direction. Gear 87. by reason of the engagement of its clutch teeth 86 with the clutch teeth 85 of the clutch element 84will turn shaft81 and therefore the worm 80 in a direction to cause the Worm Wheel to turn the beam B in a-clockwise directionas viewedin Fig. l to pay ofi warp. If the amount of feed permits the whip roll. to move towardits rearmost position then the stop; rod 65 will move'forwardly and aless amount of the next working stroke, of the actuator. lever of the worm will result.

will be effective to turn the operating lever and there will be a correspondingly reduced movement of the beam.

When the diameter of the beam diminishes due to usage of the warp it will be necessary to permit more and more of the working stroke of the actuator to be efiective to move the operating lever and this result can be attained by turning the thumb nut 74 in a direction to move the stop rod 65 rearwardly, thereby moving the rod head 66 rearwardly and permitting increased rearward movement of the pin 67 with resultant lowering of the position of the arm 57 of the operating lever so that the latter can be moved by a greater part of the working stroke of the actuator as suggested in Fig. 13. In this latter figure the actuator foot 56 is in lowest position due to the forward position of the lay and the operating arm 57 is in low position, see dotted lines, to which it has been able to move by adjustment of the thumb nut. The operating lever can therefore utilize practically the entire working stroke of the actuator.

Because the gears 8'7 and 100 are in the positions shown in Figs. 2 and 5 shaft 81 will have twice the angular movement of shaft 95 so that a relatively rapid turning It is found in practice that when the gears are as shown in Fig. 5 the letotf is elfective to deliver warp for the satisfactory weaving of fabrics ranging from very coarse up to a finer range, but for weaving fabrics in a still higher range in which even more picks to the inch are required the gears 87 and 100 are interchanged by removal of bearing 96 which permits these gears to be slid endwise to the left off their respective shafts and transposed, the smaller gear 87 being put on shaft 95 and the larger gear 100 being put ,on shaft 81, as shown in Fig. 10. Gear 87 has a slot 130 to receive the key 101 on shaft 95.

After the gears have been thus transposed the shaft 81 will turn only half as fast as shaft 95 and the correspondingly reduced rate of rotation of the worm will permit the weaving of fabrics in a higher range than was possible before the gears were interchanged. When the interchange is made the clutch teeth 126 of gear 100 will engage the teeth 85 of the clutch element 84.

The clutch unit C is of the type which will cause rotation of shaft 95 in one direction only. No particular claim is made herein for the construction of the clutch since the latter is of a commercially available type but when the operating lever arm 57 descends during a nonworking stroke of the actuator lever the arm 107 will move down with it and move the shell 102 without causing a reverse turning of the shaft 95. The use of this kind of clutch unit results in very little if any lost motion between the arm 107 and the shaft 95 when the operating lever is being moved by a working stroke of the actuator lever. The clutch unit would prevent reverse turning of the beam after a pick-out operation if it were geared permanently to the worm and it is for this reason that the clutch element 84 is made so that it can he slid out of engagement with the clutch teeth of gear 87 or 100, whichever is on shaft 81. When the lock 115 is holding the element 84 away from the gear on shaft 81 the worm can be turned manually in either direction as already described. I

Thus far the description herein has set forth a pre ferred form of the invention wherein the gears 87 and 100 are able to take care of a wide range of fabrics from a few picks per inch to a much larger number of picks per inch. If it is desired to provide additional gearing to take care of the middle part of the whole range possible with gears 87 and 100 other gears 135 and 136 may be substituted for the two gears already described, these other gears being the modified form of the invention wherein there is a less difference in their pitch diameter's. These additional gears 135 and 136, shown diagrammatically in Fig. 11, may be in the ratio of 3 to 2 respectively but it is within the spirit of the invention to have the gears shown in Fig. 11 of equal pitch diameter. When gear 135 is applied to shaft and gear 136 to shaft 81 the lower or coarse end of the range possible will be somewhat finer than that possible when gear is on shaft 95, and when gears and 136 are interchanged then the upper limit of range may be somewhat less than that which can be attained when gear 87 is on shaft 95.

From the foregoing it will be seen that the invention sets forth a letotf mechanism adaptable for the weaving of a wide range of fabrics with respect to weft threads per inch. The gears on the shaft 81 and 95 are-of unequal size so that by the removal of bearing 96 the gears can be slipped off their shafts and transposed to change the gear ratio between the shafts. In the preferred form of the invention the ratio has been arbitrarily shown at 2 to l but the invention is not limited to this ratio and the latter can be chosen to suit any special condition with respect either to very coarse or very fine fabrics. Also, the clutch element 84 can be slid along the shaft 81 to disconnect it from the gear on the shaft 81, thus interrupting the driving connections between the clutch unit C and the worm to permit the latter to be reversed manually. Furthermore, provision is made for enabling the operating lever 58 to utilize varying amounts of the working stroke of the actuator lever 50 depending upon the position of the whip roll and also upon the setting of the thumb nut on the rod 65. If desired a second set of unequal gears may be employed such as suggested in Fig. 11, the ratio of the gears 135 and 136 being different from that of the gears 87 and 100. In some instances,

the gears shown in Fig. 11 can be equal in which event they would not be interchanged, but other features of the invention, such as the relation between the actuator, the operating lever, the stop rod 65 and the whip roll, and also the disconnection of the clutch element 84 from the gear on shaft 81 would be present and have the advantages set forth hereinbefore. Also, the actuator has its Working stroke on the rearward motion of the lay so that the warp beam can be turned without having the. fell of the cloth subjected to pressure by the reed, a condition which might otherwise interfere with smooth operation of the mechanism.

Having now particularly described and ascertained the nature of the invention and in what manner the same is to be performed, what is claimed is:

1. In letoif mechanism for a loom having a rotatable warp beam, a whip roll over which the warp extends movable forwardly from a normal rearmost position due to increase in the tension of the warp, means tending to move the Whip roll to said rearmost position, a worm wheel operatively connected with the beam to turn therewith, a worm meshing with the worm wheel effective when turned in a given direction to cause the wheel to turn the beam to pay off warp, a gear operatively connected to the worm to rotate the latter when the gear rotates, a second gear meshing with the first gear, a rotary clutch unit operatively connected to said second gear effective when turned in one direction to cause said gears to cooperate to turn said worm in said given direction but ineffective when turned in the opposite direction to cause turning of said gears, an actuator having a working stroke and a return stroke each beat of the loom, a movable stop the position of which is determined by the whip roll, clutch unit operating means the position of which is normally determined by engagement with the stop effecting a variation depending upon the position of the stop in the amount of the working stroke of the actuator operative to cause movement-of the operating means away from said stop to move the clutch unit in said one direction to turn the beam topay off warp, resilient means effective to move said operating means toward said stop when the actuator has a return stroke, said gears being of unequal size and being interchangeable nestles;

7 from one setting to another so thatin one setting of the gears the letofi is adapted for the weaving of relatively coarse fabrics and is adapted for the weaving of relatively fine fabrics when the gears are in the other setting.

2. In letofi? mechanism for a loom having a rotatable warp beam, a whip roll over which the warp extends movable forwardly from a normal rearmost position due to increase in the tension of the warp, means tending to move the Whip. roll to said rearmost position, a worm wheel operatively connected with the beam to turn therewith, a worm meshing with the Worm wheel efi'ective when turned in a given direction to cause the wheel to turn the beam to pay off warp, a gear operatively connected' to' the worm to rotate the latter when the gear rotates, a second gear meshing with the first gear, a rotary clutch unitoperatively connected to said second gear effective when turned in one direction to cause said gears to cooperate to turn said worm in said given direction but ineffective when turned in the opposite direction to cause turning of said' gears, an actuator having a working' stroke and a return stroke each beat of the loom, a movable stop the position of which is determined by the whip roll, clutch unit operating means the position of which is' normally determined by engagement with the stop effecting a variation depending upon the position of the stop in the amount of the working stroke of the actuator operative to cause movement of the operating means away from said stop to move the clutch unit in said one direction to turn the beam to pay off warp, resilient means effective to move said operating means toward said stop when the actuator has a return stroke, a clutch elementoperatively interposed between the worm and the gear corresponding thereto, and means normally efiective to operatively engage the clutch element with the gear corresponding thereto but yieldable to permit the clutch element to become disengaged from the gear to permit-turning of the wormindependently of the gear.

3. In letoif mechanism for aloom having a rotatable warp beam, a whip roll over which the warp extends movable forwardly'from anormal rearmost position due to increase in thetension of the warp, means tending to move the whip roll to said rearmost position, a worm wheel operatively connected with the beam to turn therewith, a worm meshing with the worm wheel eil'fective when turned in a given direction to cause the wheel to turn the beam to pay off warp, a gear operatively connected to the worm to rotate the latter when the gear rotates, a second gear meshing with the first gear, a rotary clutch-unit operatively connected to said second gear effective when turned in one direction to cause said gears to cooperate to turn said worm in said given direction but ineffective when turned in the opposite direction to cause turning of said gears, an actuator having a working:v stroke and a return stroke each beat of the loom, a movablestop the position of whichis determined by the whip roll, clutch unit operating means the position of which is normally determined by engagement with the stop effecting a variation depending upon the position of the stop'in the amount of the working stroke of the actuator. operative to cause movement of the operating means away from said stop to move the clutch unit in said one direction to turn the beam to pay off warp, resilient means effective to move said operating means toward said stop when the actuator has a return stroke, a shaft for'the worm and the gear corresponding, another shaft for the: second gear and the clutch unit, and detachable driving means interposed between the gear on the first shaft and the worm to enable the worm to turn independently ofxthe gears.

4. In letoft mechanism for a loom having a rotatable warp, beam, a whip roll over which the warp extends movableforwardlyfrom a normal'rearmost position due 7 8 to increase in the tension of thew arp, means tending to move the'whip roll to saidrear'most position, a worni wheel operatively connected with the beam to turn therewith, a worm meshing with the worm wheel effective when turned in a given direction to cause the wheel to turn the beam topay off Warp, a gear operatively con nected to the worm to rotate the latter When the gear rotates, a second gear meshing with the first gear, a rotary clutch unit operatively connected to said second gear eltective when turned in one direction to cause said gears to cooperate to" turn said worm in said given direction but ineffective when turned in the opposite direction to cause turning of said gears, an actuator having a working stroke and a return stroke each beat of the loom, a movable stop the position of which is determined by the whip roll, clutch unit operating means the position of which is normally determined by engagement with the stop effecting a variation depending upon the position of the stop in the amount of the working stroke of the actuator' operative to cause movement of the operating means away from said'stop' to move the clutch unit in said one direction to turn the beam to pay ott warp, resilient means effective to move said operating means toward said stop when the actuator has a return stroke, said gears being interchangeable so that either one of them can be associated with the worm, and a clutch element operatively interposed between the worm and the gear associated therewith, said clutch element being provided with clutch teeth, and each of said gears being also provided with clutch teeth capable of engaging the clutch teeth of the clutch element, depending upon which of said gears is associated with the clutch element.

5. In letoif mechanism for a m having a rotatable warp beam, a whip roll over which the warp extends movable forwardly from a normal rearmost position due to i-ncreas'e'in the tension of the warp, means tending to move" the whip roll to said rearmost position, a worm wheel operatively connected with the beam to turn therewith, a worm meshing with the worm wheel efiective when turned in a given direction to cause the wheel to turn the beam to pay off warp, a gear operatively connected to the worm to rotate the latter when the gear rotates, a second gear meshing with the first gear, a rotary clutch unit operatively connected to said second gear efiective when turned in one direction to cause said gears to cooperate to turn said worm in said given direction but ineffective when turned in the opposite direction to cause turning of said gears, an actuator having a working stroke and a return stroke each beat of the loom, a movable stop the position of which is determined by the whip roll, clutch unit operating means the position of which is normally determined by engagement with the stop effecting a variation depending upon the position of the stop in the amount of the working stroke of the actuator operative to causemovement of the operating means away from said stop to move the clutch unit in said one direction to turn the beam to pay cit warp, resilient means effective to move said operating means toward said stop when the actuator has a return stroke, two parallel shafts, one for each gear, and a removable bearing normally holding said shafts in position but when removed enabling said gears to be removed from the shafts so they can be interchanged with respect to their shafts, the gears being of unequal size.

References Cited in the file of this patent UNITED STATES PATENTS 1,749,120 Baker Mar. 4, 1930 2,585,167 Picanol Feb. 12, 1952 FOREIGN PATENTS 605,468 Great Britain July 23,v 1948 

